Liquid Crystals for Organic Field-Effect Transistors

  • Mary O’NeillEmail author
  • Stephen M. Kelly
Part of the Springer Series in Materials Science book series (SSMATERIALS, volume 169)


Columnar, smectic and lamellar polymeric liquid crystals are widely recognized as very promising charge-transporting organic semiconductors due to their ability to spontaneously self-assemble into highly ordered domains in uniform thin films over large areas. The transport properties of smectic and columnar liquid crystals are discussed in  Chaps. 2 and  3. Here we examine their application to organic field-effect transistors (OFETs): after a short introduction in Sect. 9.1 we introduce the OFET configuration and show how the mobility is measured in Sect. 9.2. Section 9.3 discusses polymeric liquid crystalline semiconductors in OFETs. We review research that shows that annealing of polymers in a fluid mesophase gives a more ordered microcrystalline morphology on cooling than that kinetically determined by solution processing of the thin film. We also demonstrate the benefits of monodomain alignment and show the application of liquid crystals in light-emitting field-effect transistors. Some columnar and smectic phases are highly ordered with short intermolecular separation to give large π-π coupling. We discuss their use in OFETs in Sects. 9.4, and 9.5 respectively. Section 9.6 summarises the conclusions of the chapter.


Liquid Crystal Organic Semiconductor Hole Mobility Charge Carrier Mobility Liquid Crystalline Polymer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


  1. 1.
    Coropceanu, V., Cornil, J., da Silva Filho, D.A., Olivier, Y., Silbey, R., Brédas, J.L.: Charge transport in organic semiconductors. Chem. Rev. 107(4), 926–952 (2007)CrossRefGoogle Scholar
  2. 2.
    Sirringhaus, H.: Device physics of solution-processed organic field-effect transistors. Adv. Mater. 17(20), 2411–2425 (2005). doi: 10.1002/adma.200501152 CrossRefGoogle Scholar
  3. 3.
    Zaumseil, J., Sirringhaus, H.: Electron and ambipolar transport in organic field-effect transistors. Chem. Rev. 107(4), 1296–1323 (2007)CrossRefGoogle Scholar
  4. 4.
    Allard, S., Forster, M., Souharce, B., Thiem, H., Scherf, U.: Organic semiconductors for solution-processable field-effect transistors (OFETs). Angew. Chem. Int. Ed. 47(22), 4070–4098 (2008)CrossRefGoogle Scholar
  5. 5.
    Newman, C.R., Frisbie, C.D., da Silva, D.A., Bredas, J.L., Ewbank, P.C., Mann, K.R.: Introduction to organic thin film transistors and design of n-channel organic semiconductors. Chem. Mater. 16(23), 4436–4451 (2004). doi: 10.1021/cm049391x CrossRefGoogle Scholar
  6. 6.
    Sirringhaus, H., Brown, P.J., Friend, R.H., Nielsen, M.M., Bechgaard, K., Langeveld-Voss, B.M.W., Spiering, A.J.H., Janssen, R.A.J., Meijer, E.W., Herwig, P., De Leeuw, D.M.: Two-dimensional charge transport in self-organized, high-mobility conjugated polymers. Nature 401(6754), 685–688 (1999)ADSCrossRefGoogle Scholar
  7. 7.
    Chang, J.F., Clark, J., Zhao, N., Sirringhaus, H., Breiby, D.W., Andreasen, J.W., Nielsen, M.M., Giles, M., Heeney, M., McCulloch, I.: Molecular-weight dependence of interchain polaron delocalization and exciton bandwidth in high-mobility conjugated polymers. Phys. Rev. B Conden. Matter Mater. Phys. 74(11) (2006)Google Scholar
  8. 8.
    Kline, R.J., McGehee, M.D.: Morphology and charge transport in conjugated polymers. Polym. Rev. 46(1), 27–45 (2006)Google Scholar
  9. 9.
    Kline, R.J., McGehee, M.D., Toney, M.F.: Highly oriented crystals at the buried interface in polythiophene thin-film transistors. Nat. Mater. 5(3), 222–228 (2006)ADSCrossRefGoogle Scholar
  10. 10.
    Tsao, H.N., Mullen, K.: Improving polymer transistor performance via morphology control. Chem. Soc. Rev. 39(7), 2372–2386 (2010)CrossRefGoogle Scholar
  11. 11.
    Ong, B.S., Wu, Y., Liu, P., Gardner, S.: High-performance semiconducting polythiophenes for organic thin-film transistors. J. Am. Chem. Soc. 126(11), 3378–3379 (2004)CrossRefGoogle Scholar
  12. 12.
    McCulloch, I., Heeney, M., Bailey, C., Genevicius, K., MacDonald, I., Shkunov, M., Sparrowe, D., Tierney, S., Wagner, R., Zhang, W., Chabinyc, M.L., Kline, R.J., McGehee, M.D., Toney, M.F.: Liquid-crystalline semiconducting polymers with high charge-carrier mobility. Nat. Mater. 5(4), 328–333 (2006)ADSCrossRefGoogle Scholar
  13. 13.
    McCulloch, I., Heeney, M., Chabinyc, M.L., Delongchamp, D., Kline, R.J., Cölle, M., Duffy, W., Fischer, D., Gundlach, D., Hamadani, B., Hamilton, R., Richter, L., Salleo, A., Shkunov, M., Sparrowe, D., Tierney, S., Zhang, W.: Semiconducting thienothiophene copolymers: design, synthesis, morphology, and performance in thin-film organic transistors. Adv. Mater. 21(10–11), 1091–1109 (2009)CrossRefGoogle Scholar
  14. 14.
    Heeney, M., Bailey, C., Genevicius, K., Shkunov, M., Sparrowe, D., Tierney, S., McCulloch, I.: Stable polythiophene semiconductors incorporating thieno[2,3-6]thiophene. J. Am. Chem. Soc. 127(4), 1078–1079 (2005)CrossRefGoogle Scholar
  15. 15.
    Hamadani, B.H., Gundlach, D.J., McCulloch, I., Heeney, M.: Undoped polythiophene field-effect transistors with mobility of 1 cm2 V−1 s−1. Appl. Phys. Lett. 91(24), P243512 (2007)ADSCrossRefGoogle Scholar
  16. 16.
    Li, Y., Wu, Y., Liu, P., Birau, M., Pan, H., Ong, B.S.: Poly(2,5-bis(2-thienyl)-3,6-dialkylthieno[3,2-b]thiophene)s-high-mobility semiconductors for thin-film transistors. Adv. Mater. 18(22), 3029–3032 (2006)CrossRefGoogle Scholar
  17. 17.
    Kim, D.H., Lee, B.L., Moon, H., Kang, H.M., Jeong, E.J., Park, J.I., Han, K.M., Lee, S., Yoo, B.W., Koo, B.W., Kim, J.Y., Lee, W.H., Cho, K., Becerril, H.A., Bao, Z.: Liquid-crystalline semiconducting copolymers with intramolecular donor-acceptor building blocks for high-stability polymer transistors. J. Am. Chem. Soc. 131(17), 6124–6132 (2009)CrossRefGoogle Scholar
  18. 18.
    Delongchamp, D.M., Kline, R.J., Jung, Y., Lin, E.K., Fischer, D.A., Gundlach, D.J., Cotts, S.K., Moad, A.J., Richter, L.J., Toney, M.F., Heeney, M., McCulloch, I.: Molecular basis of mesophase ordering in a thiophene-based copolymer. Macromolecules 41(15), 5709–5715 (2008)ADSCrossRefGoogle Scholar
  19. 19.
    DeLongchamp, D.M., Kline, R.J., Lin, E.K., Fischer, D.A., Richter, L.J., Lucas, L.A., Heeney, M., McCulloch, I., Northrup, J.E.: High carrier mobility polythiophene thin films: structure determination by experiment and theory. Adv. Mater. 19(6), 833–837 (2007)CrossRefGoogle Scholar
  20. 20.
    Chang, J.F., Sirringhaus, H., Giles, M., Heeney, M., McCulloch, I.: Relative importance of polaron activation and disorder on charge transport in high-mobility conjugated polymer field-effect transistors. Phys. Rev. B Conden. Matter Mater. Phys. 76(20), 205204 (2007)ADSCrossRefGoogle Scholar
  21. 21.
    Sirringhaus, H., Wilson, R.J., Friend, R.H., Inbasekaran, M., Wu, W., Woo, E.P., Grell, M., Bradley, D.D.C.: Mobility enhancement in conjugated polymer field-effect transistors through chain alignment in a liquid-crystalline phase. Appl. Phys. Lett. 77(3), 406–408 (2000)ADSCrossRefGoogle Scholar
  22. 22.
    Yasuda, T., Fujita, K., Tsutsui, T., Geng, Y., Culligan, S.W., Chen, S.H.: Carrier transport properties of monodisperse glassy-nematic oligofluorenes in organic field-effect transistors. Chem. Mater. 17(2), 264–268 (2005)CrossRefGoogle Scholar
  23. 23.
    Delongchamp, D.M., Kline, R.J., Jung, Y., Germack, D.S., Lin, E.K., Moad, A.J., Richter, L.J., Toney, M.F., Heeney, M., McCulloch, I.: Controlling the orientation of terraced nanoscale “ribbons” of a poly(thiophene) semiconductor. ACS Nano 3(4), 780–787 (2009)CrossRefGoogle Scholar
  24. 24.
    Lee, M.J., Gupta, D., Zhao, N., Heeney, M., McCulloch, I., Sirringhaus, H.: Anisotropy of charge transport in a uniaxially aligned and chain-extended, high-mobility, conjugated polymer semiconductor. Adv. Funct. Mater. 21(5), 932–940 (2011)CrossRefGoogle Scholar
  25. 25.
    Gwinner, M.C., Khodabakhsh, S., Giessen, H., Sirringhaus, H.: Simultaneous optimization of light gain and charge transport in ambipolar light-emitting polymer field-effect transistors. Chem. Mater. 21(19), 4425–4433 (2009)CrossRefGoogle Scholar
  26. 26.
    Zaumseil, J., Groves, C., Winfield, J.M., Greenham, N.C., Sirringhaus, H.: Electron-hole recombination in uniaxially aligned semiconducting polymers. Adv. Funct. Mater. 18(22), 3630–3637 (2008)CrossRefGoogle Scholar
  27. 27.
    Zaumseil, J., Donley, C.L., Kim, J.S., Friend, R.H., Sirringhaus, H.: Efficient top-gate, ambipolar, light-emitting field-effect transistors based on a green-light-emitting polyfluorene. Adv. Mater. 18(20), 2708–2712 (2006)CrossRefGoogle Scholar
  28. 28.
    Gwinner, M.C., Khodabakhsh, S., Song, M.H., Schweizer, H., Giessen, H., Sirringhaus, H.: Integration of a rib waveguide distributed feedback structure into a light-emitting polymer field-effect transistor. Adv. Funct. Mater. 19(9), 1360–1370 (2009)CrossRefGoogle Scholar
  29. 29.
    O’Neill, M., Kelly, S.M.: Ordered materials for organic electronics and photonics. Adv. Mater. 23(5), 566–584 (2011)CrossRefGoogle Scholar
  30. 30.
    Funahashi, M.: Development of liquid-crystalline semiconductors with high carrier mobilities and their application to thin-film transistors. Polym. J. 41(6), 459–469 (2009)CrossRefGoogle Scholar
  31. 31.
    Pisula, W., Zorn, M., Chang, J.Y., Mullen, K., Zentel, R.: Liquid crystalline ordering and charge transport in semiconducting materials. Macromol. Rapid Commun. 30(14), 1179–1202 (2009)CrossRefGoogle Scholar
  32. 32.
    Van De Craats, A.M., Warman, J.M., Fechtenkötter, A., Brand, J.D., Harbison, M.A., Müllen, K.: Record charge carrier mobility in a room-temperature discotic liquid-crystalline derivative of hexabenzocoronene. Adv. Mater. 11(17), 1469–1472 (1999)CrossRefGoogle Scholar
  33. 33.
    Pisula, W., Menon, A., Stepputat, M., Lieberwirth, I., Kolb, U., Tracz, A., Sirringhaus, H., Pakula, T., Müllen, K.: A zone-casting technique for device fabrication of field-effect transistors based on discotic hexa-perihexabenzocoronene. Adv. Mater. 17(6), 684–688 (2005)CrossRefGoogle Scholar
  34. 34.
    Xiao, S., Myers, M., Miao, Q., Sanaur, S., Pang, K., Steigerwald, M.L., Nuckolls, C.: Molecular wires from contorted aromatic compounds. Angew. Chem. Int. Ed. 44(45), 7390–7394 (2005)CrossRefGoogle Scholar
  35. 35.
    Tracz, A., Jeszka, J.K., Watson, M.D., Pisula, W., Mullen, K., Pakula, T.: Uniaxial alignment of the columnar super-structure of a hexa (alkyl) hexa-peri-hexabenzocoronene on untreated glass by simple solution processing. J. Am. Chem. Soc. 125(7), 1682–1683 (2003)CrossRefGoogle Scholar
  36. 36.
    Tsao, H.N., Pisula, W., Liu, Z., Osikowicz, W., Salaneck, W.R., Müllen, K.: From ambi- To unipolar behavior in discotic dye field-effect transistors. Adv. Mater. 20(14), 2715–2719 (2008)CrossRefGoogle Scholar
  37. 37.
    Iino, H., Hanna, J.: Ambipolar charge carrier transport in liquid crystals. Opto-Electron. Rev. 13(4), 295–302 (2005)Google Scholar
  38. 38.
    Ponomarenko, S.A., Kirchmeyer, S., Elschner, A., Alpatova, N.M., Halik, M., Klauk, H., Zschieschang, U., Schmid, G.: Decyl-end-capped thiophene-phenylene oligomers as organic semiconducting materials with improved oxidation stability. Chem. Mater. 18(2), 579–586 (2006)CrossRefGoogle Scholar
  39. 39.
    Van Breemen, A.J.J.M., Herwig, P.T., Chlon, C.H.T., Sweelssen, J., Schoo, H.F.M., Setayesh, S., Hardeman, W.M., Martin, C.A., De Leeuw, D.M., Valeton, J.J.P., Bastiaansen, C.W.M., Broer, D.J., Popa-Merticaru, A.R., Meskers, S.C.J.: Large area liquid crystal monodomain field-effect transistors. J. Am. Chem. Soc. 128(7), 2336–2345 (2006)CrossRefGoogle Scholar
  40. 40.
    Vlachos, P., Mansoor, B., Aldred, M.P., O’Neill, M., Kelly, S.M.: Charge-transport in crystalline organic semiconductors with liquid crystalline order. Chem. Commun. 23, 2921–2923 (2005)CrossRefGoogle Scholar
  41. 41.
    Oikawa, K., Monobe, H., Nakayama, K.I., Kimoto, T., Tsuchiya, K., Heinrich, B., Guillon, D., Shimizu, Y., Yokoyama, M.: High carrier mobility of organic field-effect transistors with a thiophene-naphthalene mesomorphic semiconductor. Adv. Mater. 19(14), 1864–1868 (2007)CrossRefGoogle Scholar
  42. 42.
    Funahashi, M., Zhang, F., Tamaoki, N.: High ambipolar mobility in a highly ordered smectic phase of a dialkylphenylterthiophene derivative that can be applied to solution-processed organic field-effect transistors. Adv. Mater. 19(3), 353–358 (2007)CrossRefGoogle Scholar
  43. 43.
    Zhang, F., Funahashi, M., Tamaoki, N.: High-performance thin film transistors from semiconducting liquid crystalline phases by solution processes. Appl. Phys. Lett. 91(6), 063515 (2007)ADSCrossRefGoogle Scholar
  44. 44.
    Zhang, F., Funahashi, M., Tamaoki, N.: Thin-film transistors based on liquid-crystalline tetrafluorophenylter thiophene derivatives: thin-film structure and carrier transport. Org. Electron. Phys. Mater. Appl. 10(1), 73–84 (2009)Google Scholar
  45. 45.
    Liu, J., Zhang, R., Osaka, I., Mishra, S., Javier, A.E., Smilgies, D.M., Kowalewski, T., McCullough, R.D.: Transistor paint: environmentally stable N-alkyldithienopyrrole and bithiazole-based copolymer thin-film transistors show reproducible high mobilities without annealing. Adv. Funct. Mater. 19(21), 3427–3434 (2009)CrossRefGoogle Scholar
  46. 46.
    Ebata, H., Izawa, T., Miyazaki, E., Takimiya, K., Ikeda, M., Kuwabara, H., Yui, T.: Highly soluble [1]benzothieno[3,2-b]benzothiophene (BTBT) derivatives for high-performance, solution-processed organic field-effect transistors. J. Am. Chem. Soc. 129(51), 15732–15733 (2007)CrossRefGoogle Scholar
  47. 47.
    Izawa, T., Miyazaki, E., Takimiya, K.: Molecular ordering of high-performance soluble molecular semiconductors and re-evaluation of their field-effect transistor characteristics. Adv. Mater. 20(18), 3388–3392 (2008)CrossRefGoogle Scholar
  48. 48.
    Iino, H., Hanna, J.I.: Availability of liquid crystallinity in solution processing for polycrystalline thin films. Adv. Mater. 23(15), 1748–1751 (2011)CrossRefGoogle Scholar
  49. 49.
    Fujiwara, T., Locklin, J., Bao, Z.: Solution deposited liquid crystalline semiconductors on a photoalignment layer for organic thin-film transistors. Appl. Phys. Lett. 90(23), 232108 (2007)ADSCrossRefGoogle Scholar
  50. 50.
    O’Neill, M., Kelly, S.M.: Photoinduced surface alignment for liquid crystal displays. J. Phys. D: Appl. Phys. 33(10), R67–R84 (2000)CrossRefGoogle Scholar
  51. 51.
    Smits, E.C.P., Mathijssen, S.G.J., Van Hal, P.A., Setayesh, S., Geuns, T.C.T., Mutsaers, K.A.H.A., Cantatore, E., Wondergem, H.J., Werzer, O., Resel, R., Kemerink, M., Kirchmeyer, S., Muzafarov, A.M., Ponomarenko, S.A., De Boer, B., Blom, P.W.M., De Leeuw, D.M.: Bottom-up organic integrated circuits. Nature 455(7215), 956–959 (2008)ADSCrossRefGoogle Scholar
  52. 52.
    Hikmet, R.A.M., Lub, J.: Anisotropic networks and gels obtained by photopolymerisation in the liquid crystalline state: synthesis and applications. Prog. Polym. Sci. Oxf 21(6), 1165–1209 (1996)CrossRefGoogle Scholar
  53. 53.
    Kelly, S.M.: Anisotropic networks, elastomers and gels. Liq. Cryst. 24(1), 71–82 (1998)CrossRefGoogle Scholar
  54. 54.
    Hikmet, R.A.M., Lub, J., Broer, D.J.: Anisotropic networks formed by photopolymerization of liquid-crystalline molecules. Adv. Mater. 3(7–8), 392–394 (1991)CrossRefGoogle Scholar
  55. 55.
    Broer, D.J., Boven, J., Mol, G.N., Challa, G.: In-situ photopolymerization of oriented liquid-crystalline acrylates, 3. Oriented polymer networks from a mesogenic diacrylate. Makromol. Chem. 190, 2255–2268 (1989)CrossRefGoogle Scholar
  56. 56.
    Kelly, S.M.: Anisotropic networks. J. Mater. Chem. 5(12), 2047–2061 (1995)CrossRefGoogle Scholar
  57. 57.
    McCulloch, I., Coelle, M., Genevicius, K., Hamilton, R., Heckmeier, M., Heeney, M., Kreouzis, T., Shkunov, M., Zhang, W.: Electrical properties of reactive liquid crystal semiconductors. Jpn. J. Appl. Phys. 47(1 PART 2), 488–491 (2008)ADSCrossRefGoogle Scholar
  58. 58.
    McCulloch, I., Zhang, W., Heeney, M., Bailey, C., Giles, M., Graham, D., Shkunov, M., Sparrowe, D., Tierney, S.: Polymerisable liquid crystalline organic semiconductors and their fabrication in organic field effect transistors. J. Mater. Chem. 13(10), 2436–2444 (2003)CrossRefGoogle Scholar
  59. 59.
    Huisman, B.H., Valeton, J.J.P., Nijssen, W., Lub, J., Ten Hoeve, W.: Oligothiophene-based networks applied for field-effect transistors. Adv. Mater. 15(23), 2002–2005 (2003)CrossRefGoogle Scholar
  60. 60.
    Baldwin, R.J., Kreouzis, T., Shkunov, M., Heeney, M., Zhang, W., McCulloch, I.: A comprehensive study of the effect of reactive end groups on the charge carrier transport within polymerized and nonpolymerized liquid crystals. J. Appl. Phys. 101(2) (2007)Google Scholar
  61. 61.
    Farrar, S.R., Contoret, A.E.A., O’Neill, M., Nicholls, J.E., Richards, G.J., Kelly, S.M.: Nondispersive hole transport of liquid crystalline glasses and a cross-linked network for organic electroluminescence. Phys. Rev. B 66(12) (2002). doi: doi:12510710.1103/PhysRevB.66.125107
  62. 62.
    Hoang, M.H., Cho, M.J., Kim, D.C., Kim, K.H., Shin, J.W., Cho, M.Y., Js, J., Choi, D.H.: Photoreactive Ï€-conjugated star-shaped molecules for the organic field-effect transistor. Org. Electron. Phys. Mater. Appl. 10(4), 607–617 (2009)Google Scholar
  63. 63.
    Arias, A.C., MacKenzie, J.D., McCulloch, I., Rivnay, J., Salleo, A.: Materials and applications for large area electronics: solution-based approaches. Chem. Rev. 110(1), 3–24 (2010)CrossRefGoogle Scholar
  64. 64.
    Tsao, H.N., Cho, D., Andreasen, J.W., Rouhanipour, A., Breiby, D.W., Pisula, W., Müllen, K.: The influence of morphology on high-performance polymer field-effect transistors. Adv. Mater. 21(2), 209–212 (2009)CrossRefGoogle Scholar
  65. 65.
    Zeng, L., Yan, F., Wei, S.K.H., Culligan, S.W., Chen, S.: Synthesis and processing of monodisperse oligo(fluorene-co-bithiophene)s into oriented films by thermal and solvent annealing. Adv. Funct. Mater. 19(12), 1978–1986 (2009)CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  1. 1.Department of Physics and MathematicsUniversity of HullHullUK
  2. 2.Department of ChemistryUniversity of HullHullUK

Personalised recommendations